With the present interest in monitoring power usage of individual circuits in a residence or business in order to insure that electric power is being used in the most economic manner some circuits have proven to be more difficult in obtaining accurate power measurements than others. Most circuits are either single phase or balanced two phase, both of which are easily monitored by using one current transformer (CT) to measure current through the circuit, which can be used to determine the quantity of power consumed by loads connected to the circuit. In a single phase circuit of FIG. 1 generally indicated by reference numeral 10, the CT is placed on the conductor L1 providing power to the single phase load 14. The measured current I1 is multiplied by the measured voltage VL1-N to determine the total power used by the single phase load.P=I1×VL1-N 
In a balanced two phase circuit of FIG. 2, generally represented by reference numeral 18, the CT can be placed on either of the conductor L1 or L2 providing power to the balanced two phase load 22 because the current I1 in conductor L1 is equal to the current I3 in conductor L2. Therefore, the current I1 in L1 multiplied by voltage VL1-N multiplied by 2 or the current I3 in L2 multiplied by voltage VL2-N multiplied by 2 will produce the total power used by the balanced two phase load 22.P=I1×VL1-N×2 or P=I3×VL2-N×2
However, some two phase circuits are not balanced, such as the circuit generally indicated by reference numeral 26 in FIG. 3. The unbalanced circuit 26 has both a two phase load 22 and a single phase load 14. These unbalanced circuits 26 are generally found in devices such as an electric clothes dryer, which is the most common example of this type of two phase circuit in residential applications. With respect to the clothes dryer, the single phase load 14 (generally a motor, control electronics and/or a timer) will always be ON when the two phase load 22 (generally a heater) is ON, and can be ON when the two phase load 22 is OFF. Therefore, using a single CT on either of the conductors L1 or L2 to measure current in unbalanced two phase circuit 26, and using the balanced load calculation to determine total current through the circuit, as described above, cannot result in an accurate determination of total consumed power for the unbalanced two phase circuit 26. If the single CT is installed on the conductor L1, which provides power to both the two phase load 22 and the single phase load 14, the determined power consumption for the circuit will be too high. This is because the CT will measure current I1, which is the current passing through the two phase load 22 and current I2, which is the current passing through the single phase load 14.P<I1×VL1-N×2
If a single CT is installed on conductor L2 the determined power consumption for the circuit will be too low because the CT will only measure current I3, which is only the current passing through the two phase load 22.P>I3×VL2-N×2
Therefore, installing CTs on both conductors L1 and L2, and adding the power calculated from the current measured by each of the CTs is the obvious solution for accurate power monitoring in unbalanced two phase circuit 26.P=(I1×VL1-N)+(I3×VL2-N)
However, there may not be sufficient room in the load center for using two CTs on one circuit or it could mean that the number of circuits monitored must be reduced. Therefore, a means to accurately monitor power usage on unbalanced two phase circuits such as circuit 26 having both a single phase load 14 and a two phase load 22 with one CT is desirable.